Improved efficiency of ternary the blend polymer solar cells by doping a narrow band gap polymer material

A series of P3HT:PC₇₁BM polymer solar cells (PSCs) with different PIDTDTQx doping concentrations were fabricated to investigate the effect of the PIDTDTQx as a complementary electron donor on the performance of PSCs. The power conversion efficiency (PCE) of the optimized ternary blend PSCs (with 2 wt% PIDTDTQx) reached 3.87%, which is 28% higher than that of the PSCs based on P3HT:PC₇₁BM (control cells). The short-circuit current density (J_sc) was increased to 10.20 mA/cm2 compared with the control cells. The PCE improvement could be attributed to more photon harvest and charge carrier transport by appropriate doping PIDTDTQx. The energy transfer from P3HT to PIDTDTQx was demonstrated from the 650 nm emission intensity decrease and the red-shifted emission peaks from 725 nm to 737 nm along with the increase of PIDTDTQx doping concentrations.